The present invention relates to computer telephony. More specifically, the present invention relates to telephone servers for transferring and forwarding analog caller identification data from incoming telephone calls.
Present day analog telephone systems in the United States typically rely upon standards set by Bellcore, the standards division of the former Bell Telephone Company. These exhaustive standards detail the magnitudes of a variety of telephone related signals, the periods of signals, the timings of signals, and the like. For example, these Bellcore standards specify a range of voltages necessary to power an analog telephone, a range for voltages necessary to ring a ringer of a telephone, methods for indicating when messages are waiting in a voice mail-type system, and the like. Many other such standards are also described, including the methods for encoding analog information, and the like.
In the past, typical private branch exchange (PBX) systems for large corporations included computer systems having proprietary switching hardware and proprietary control software. These traditional PBX systems were very costly in terms of the hardware and the software required, as well as very costly in terms of the maintenance and the service required. For example, traditional PBX systems typically ranged in cost of tens of thousands of dollars for a simple PBX system to hundreds of thousands of dollars for a large PBX system and on up. Such PBX systems were thus very costly, especially for smaller to medium sized businesses.
Within the past two decades, the PBX industry has migrated from traditional analog switching to high-speed digital switching systems. As a result of the conversion to digital switching, there has been a tremendous increase in telephone and switching functionality. For example, functionality such as call forwarding, conference calling, caller identification, and the like became relatively straightforward to program, to implement, and to maintain.
In order to provide the benefits of digital PBX system to users, digital telephones were developed for use with the respective PBX systems. With such digital telephones, the telephone signals, such as ringing, and voice, are typically transmitted in a conventional manner. However, additional digital data lines were provided to allow the user to send and receive digital data to and from the PBX system. For example, typical digital data included indicator lights, such as a message indicator light, telephone numbers of internal and external callers, speed dial functionality, do not disturb requests, and the like. These digital PBX systems, however, were still very expensive for small to medium sized businesses.
Only recently have solutions been developed to reduce the cost of PBX. This was due in part to the increased processing power of personal computers and the availability of more robust real-time multi-processing, multi-threaded operating systems. Other reasons for the paradigm shift from traditional PBX systems to "computer telephony" was the introduction of dedicated computer plug-in boards and software that provided PBX switching functionality.
The new computer telephony integration (CTI) model has drastically reduced the costs of PBX systems by providing relatively low cost hardware and open and maintainable software. One of the pioneering companies in the field of computer telephony integration was AltiGen Communications' AltiServ.TM. and Quantum.TM. products.
One drawback faced by many companies installing a traditional PBX system was that it typically required the purchaser of the PBX system to buy only digital telephones compatible with that PBX system. For example, digital telephones from Siemens would be required to work with a Siemens PBX, and the like. Digital telephones very thus expensive. For example, the cost of a typical digital office telephone today approaches approximately $250. In contrast, in the home/consumer market, an analog telephone having the some of the same functionality as the digital office telephone, or additional functionality (e.g. cordless) costs approximately $100.
Additional drawbacks to digital telephones for traditional PBX systems included that there is little if any market for compatible accessories, for example, answering machines, and the like. In contrast, in the home market, users can simply mix and match components for use with their analog telephones. For example, typical components include computer modems, answering machines, head sets, extension cords, and the like. In the home market, due to the large number of vendors and interchangeable products, these market forces keep the prices of analog telephone equipment low.
Other drawbacks to having traditional digital PBX systems include that installation of the PBX systems typically required a high degree of custom wiring, equipment, interfaces, and the like for the digital telephones. Further, installation of additional telephone extension lines would be a major undertaking. Another drawback is that because there is a great amount of dedicated hardware required for a typical PBX system, users would be typically be locked into a particular vendor after initial purchase, even if the service and support received was unacceptable.
Thus, in light of the above, what is needed in the industry are improved methods and apparatus using analog telephone equipment for PBX systems providing extended functionality.